1. Field of the Invention
This invention relates generally to an apparatus for selectively adjusting the pitch of the strings of a stringed instrument having a fingerboard with a plurality of frets disposed thereon and particularly to a capo which is alignable with respect to the frets and has independently mounted string damping and clamping members.
2. Description of the Prior Art
Capos, that is, devices which are placed about the neck of stringed instruments and cause a string or strings of the instrument to engage one of the frets of the fingerboard to thereby shorten the effective vibrating length of the string and alter the pitch thereof, have long been used by both novice and professional performers. There are many types and styles of capos available which are appropriate for use with guitars, banjos and other similar stringed instruments.
Many conventional capos include a clamping member which engages the back of the neck and a bar or plate-like member which extends across the strings and is brought into engagement therewith by a screw, elastic, or spring means which draws the bar toward the clamping member and causes the strings to engage a fret. In order to reduce undesirable vibrations of the strings against the bar, the bar or plate is usually wrapped in a resilient vibrational dampening material such as plastic or rubber.
The capo is frequently used by the novice, who is not skilled at playing a full range of chords, or who is not capable of transposing from one key to another. By advancing the capo from fret to fret and progressing from the head toward the sound body of the instrument, the pitch of each string may be advanced in ordered increments. Then, by utilizing the same basic chord form at each step, the beginner may play music in varying keys dependent upon the placement of the capo. The performer is likewise able to vary the basic pitch of the instrument by selectively shortening the effective vibrating length of the strings and thereby achieve a variety of sound variations.
However, there are a number of basic problems associated with the use of conventional capos. Often, capos are awkward to handle and manipulate and, therefore, they are neither easily mounted on the instrument nor easily adjusted along the neck as may sometimes be desirable. Frequently the player's full attention must be given to insuring that the capo is properly aligned generally normal to the strings to insure both that there are no sound variations and that the strings are appropriately aligned and damped as they pass over the engaged fret. Not only does this positioning of the capo take time, but frequently such changes in the capo's placement must be made while performing and thus any distraction caused by the positioning of the capo is undesirable. Also, if the capo should be excessively spaced from the fret or be angled relative thereto, an irritating vibration of the string against the fret or pitch variation may result. And conversely, if the capo is placed forwardly of the fret, the string will be damped and the sound obtained thereby muted.
Normally a capo is positioned between two frets and enough pressure is applied to the bar to cause the strings to engage such frets. However, since the strings are of different diameters, the bar engages the larger strings first and sequentially engages the smaller strings. This causes unequal pressure to be applied to the strings which, in turn, causes the strings to be out of pitch with themselves due to unequal stretching.
Also it frequently becomes necessary to tune the strings with the capo in place. Many capos have a bar-like member which is wrapped or coated with a relatively wide pad of resilient material. Often it is difficult to tune a string which is being gripped by the wide capo pad due to the frictional forces between the string and the resilient material of the capo. Also since the capo extends across all the strings, as one is adjusted, the frictional engagement between the moving string and the wide capo pad may tend to cause the capo to shift slightly in relationship with the other strings and thereby cause the other strings to go slightly out of tune. Therefore, in a manner, each of the strings is connected to the other strings via the wide bar-like member and pad and thus possibly affected by the adjustment to any of the other strings.
Another style of capo currently available includes a resilient pad formed as a sleeve with several outwardly extending ridges for engaging the strings. However, the pad is formed as a single unit which is slidably fitted about the bar which extends over the strings. Therefore, although the outwardly extending ridges may reduce the area of frictional contact, because elements of the pad are integrally formed and only slidably fitted about the capo bar, a deflection at a point along one of the pad ridges may be transmitted throughout the pad. Accordingly a shifting or rotating of the pad relative to the bar is possible.
Other examples of the prior art include patents Ser. No. 468,193 to Dahlman et al; Ser. No. 620,560 to Averitt; Ser. No. 692,751 to Winchell; U.S. Pat. No. 2,604,805 to Haffner; U.S. Pat. No. 3,185,012 to Dunlop; U.S. Pat. No. 3,205,751 to Lowe; U.S. Pat. No. 3,329,055 to Milliken; U.S. Pat. No. 3,680,427 to Valentino; and U.S. Pat. No. 3,823,247 to Bauerfeind.